The NAC transcription factor gene ANAC072 is differentially expressed in Arabidopsis thaliana in response to microbe-associated molecular pattern (MAMP) molecules

Abstract

NAC (NAM, ATAF1/2 and CUC2) transcription factors (TFs) play important roles in plant development and environmental stresses, though more recently involvement in biotic stresses has also been observed, but not explored in detail. Based on a differential display library obtained from lipopolysaccharide (LPS)-elicited cells of Arabidopsis thaliana, a differentially expressed sequence tag (EST) was identified, sequenced and found to code for a NAC protein with a N-terminal NAM domain. The corresponding gene, At4g27410.3, encodes a known NAC TF, ANAC072/RD26. A. thaliana callus, cell suspensions and seedlings were used to determine the expression levels of ANAC072 after treatment with Burkholderia cepacia and associated microbe-associated molecular pattern (MAMPs) molecules. ANAC072 showed early responsiveness towards B. cepacia and its LPS and was also responsive to peptidoglycan (PGN) and the flagellin-derived peptide, flg22. The response of cultured cells was characterised by the rapid up-regulation at 10 min post elicitation. Depending on the MAMP, the response was either transient and returned to basal levels, or sustained up to 90 min. The general trend of expression was similar in seedlings compared to that of the undifferentiated cells. Transcript levels of ANAC072 were positively regulated by abscisic acid and hydrogen peroxide, but ethylene, salicylic acid, methyl jasmonate and indole acetic acid had little effect on its expression. Our data indicate that ANAC072 is an early MAMP-responsive TF, part of the altered transcriptome following MAMP perception events.